Self-compensating aneroid



Filed Dec. 1'7, 1934 3 SheetsSheer. l-

'INVENTOR Paul. KEJLLSMFHN March 14, 1939. KOLLSMAN I 2,150,771

SELF COMPENSATING ANEROID Filed Dec. 17, 1934 5 Sheets-Sheet 2 INVENTOR IjHUL KULLSMPIN B March 14, 1939. KQLLSMAN 2,150,771

SELF COMPENSATING ANEROID Filed Dec. 17, 1934 3 Sheets-Sheet 3 INVENTOR IEHUL KOLLVS'MHN Patented 14, 19391 :umrlzo STATES PATENT OFFICE .m. I Paul Kollsman, New ,York, Y. Application December 17, 1934, Serial N0. 757389 17 Claims. (01.. 137- 157) This invention relates to aneroid capsules of the type to be employed to operate an indicating device accurately in response to variations'in external pressure. An object is to render such 5 capsules self-compensating against temperature variations. The capsule is particularly well adapted-for altimeters and may be made substantially without calibration in quantity productionwith accurate compensation for temperature changes when functioning over a pressure range for atmospheric pressure varying from sea-level to an elevation of upwards of 30,000 feet.

Aneroid capsules of a preferred type-and of the general tvpe to the modification of which this .5 invention is directed are described in my prior Patent No. 1,930,899 for Aneroid and operating means therefor, granted October 17, 1933. This patent generally describes the application to, in-' dicating mechanism of aneroid capsules and also :0 sets forth various temperature compensating means, all external to the aneroid capsule.

Heretofore it has been considered infeasibleand perhaps even disastrous to the accurate functioning of ananeroid capsule to permit any substantial gas content in its chamber. I have discovered that internal gas properly proportioned V in Fig. 1;

in volume to the size, configuration and strength of .the capsule diaphragm or diaphragms is one of the best means for compensating against tem- 30 perature changes. The design of the'circula'r diaphragms' of an aneroid capsule must conform to the necessity for faithful response to variations in external pressure. One of the best designs forsuch an aneroid capsule involves the 35 provision of concentric corrugations or ringlike undulations for the circular diaphragm as described in my above mentioned prior patent. However, the chamber'naturally formed in such an aneroid capsule does not have a gas space the 40 volume of which accords with the proper functioning of a filling of gas at low pressure which is capable of functioning to compensate for temperature variations. Wherefore, an important object of my invention is to produce an aneroid 45. capsule preserving all the elements of; design necessary for faithful response to variations in external pressure and. at the same time, providing the predetermined volume for gas space in.

its chamber. V

In carrying out the objects of my invention, I have found it expedient to complement the inside contour of the corrugations of. the pressure responsive diaphragm on a member lying opposite thereto. In the capsule described in my prior 55 patent a disc shaped metal filler, preferably of aluminum and having on its opposite faces the said complementary corrugations, is satisfactory.

If thecapsule is to comprise able diaphragm. an opposing rigid wall may be provided with complementary corrugations. P osv sibly,

for some purposes,

the capsule may comprise one circular corrugated diaphragm substantially of the type tionedpatent and by another'circular described in my aforemenhave the chamber completed diaphragm having complementary circular corrugations instead of identical or symmetrical corrugations described in my said; patent.

My invention is following claims, which tive embodiments particularly pointed out in the are directed to illustraof my invention for purposes of illustration only. These embodiments are detion drawn to an embodiment;

- Fig. 2 is a similar Fig; 3 is a similar view of the embodiment shown Fig. 4 is a front specification in connecis an axial cross-.sec enlarged scale of a preferred view'of a modificationt I view of a third modification;

Fig. 5 is a. diagrammatic illustration of an application to an indicator of my improved aneroid capsule; and

Fig. 61s a combination of several aneroid capsules, two of which are completely evacuated and are of the general type set forth in'my aforementioned 'Patent No. has the gas volume of temperature comp 1,930,899, and one ofwhich its chamber regulated for ensation for the combination.

Referring particularly to Figs.'1 and 4, the' aneroid capsule D diaphragms l and peripheral flanges corrugations 5,

comprises two similar circular 2 soldered together at their 3 and l and having concentric.

necting shafts l3 and ll.- Boss structure ll, 13

is the movable operator and l2, M the fixable mount.

this embodiment the two circular diabut-a single mov- 4 6; l, 8; 9, l0 and so forth. Bosses phragms employed are identical and when secured together are symmetrical about the central axis'and about the central cross-section. Within the capsule'is the chamber A.

In order to compensate against temperature changes, I have found that the chamber A is not of theproper volume for any gas. suitable for this purpose. For

gas such as nitrogen or air, I

have foundthat the gas volume for chamber A should be limited to approximately 0.4 of the entire volume. of this 'chamber at about 30,000 feet altitude. I position within the chamber a filler disc B which may preferably be symmetrical about the central and its central crosssectionand has provisions on its opposite faces in the form of corrugations 5; B; 'l', 8';- 9', l etc. complementary to the inside faces .of the outer corrugations-5, 8; I, 8;9 and Ill etc. This filler may be. formed of any suitable solid-material such as aluminum, nickel, or it may even'be in the form ofa rigid metallic shell.

In the formshown in-Flgs. 1, and 6, leaf spring l5 may be provided reacting between the notch l6 and the inner wall ll'normally to force the ring-like enlargement or corrugation I8 jerks.

against the inner face of' the corrugation l9 to prevent chattering or relative motion between the filler B and the capsule D when the device. is subjectedtovibration, as in an airplane. This is a provision .fixing the filler B :agalnst inertia cooperate with the resilience ,of the circular diabhragms in opposing atmospheric pressure although this is not necessary.

In the embodiment 'of Fig. 2 chamber A" is formed between the inner face of one circular phragm l and the complementary corrugated inner face If and the rigid disc-shaped metal closure {20.1 Theflange 3 maybe soldered to the' flange 4'. In this embodiment the inner projection of the. concentric corrugated face 2'- towards v the circular diaphragm is regulated so as-to make;

thegas volume and, in this case, the volume it self of chamber A. that which is desired for temperature compensation from gas at lowpressure.

Fig. 3 rigid closure 20 is substituted by a resilient circular diaphragm 200 corrugated in a complementarymanner-to the corrugating of the. circular diaphragm I. The flanges 3 and 40 maybe soldered together and it may be noted that the diaphragm 206 is reentrant to form, as in the j modification of Fig. '2, a, gas chamber A'f ofa I Derature compensation.

volume predetermined to provide proper tem Fig. .5 shows the shaft lfof my capsule D ad- I justably' secured to an'lnstrument frame-30 by a set screw 3|. the shaft I3 being connected by link I80 through suitable gear mechanism with an indicator 230 in a manner similar to that set 'forth in my aforementioned patent, although this showing is intended to be merely illustrative of any employment of my new capsule in a pressure indicating'instrument.

In all of the embodiments of the invention 11- lustrated. herein the circular diaphragm having concentric corrugations of shapes and relative rugated provisions, complementary to the inside sizes designed 'to accord best for faithful response to variations in external pressure when said capsule is completely evacuated and functions at constant temperature finds its embodiment in the diaphragm I of Figs. 1, 2, 3, 4, 5 and 6. Struc ture forcompleting a closure opposite said circular' diaphragm I and for limiting the volume of the completed chamber has inside circular corcontour of said corrugations ofisaid circular diaphragm is the diaphragmj of Fig. l and the filler -B-held against post 14 by pr ng l5. This filler B has corrugations 5 complementary to the inside corrugations of circular diaphragm l form-' ing therebetween a gas space predetermlnable in volume regardless of theconcentric-corrugatlonsq .In' the structure of Figs-(2 and 3 the manner in The spring i5 may also "be employed t u' which the wall structure for completing a' closure opposite the circular diaphragm isfixed against inertia -jerks is by connectingall partsthereoi' having substantial inertia directly to the fixed post Minstead'of beingheld against saidpost somewhat yleldingly 'as-inFlg. -1. 4, In Fig. 6 I have illustrated a gang of three aneroid capsules, Das shown in Figs. 1 and .4 and capsules C of the type described in my aforementioned patent and completely evacuated. The

functioning movement of this entire gang of cap-- sules is imparted to the shaft l3 ofthe left-most capsule relatively to the support 30. When em-.

' playing one of my improved capsulesD in a gang.

although it isstill preferable to maintainthe volume-of'gas space'in, chamber A l approximate ly 0.4 of the. entire volume of chamber A inexpanded condition, I prefer to-employ a filling of ;gas such as nitrogen or, air at a pressure of approximatelythree inches of mercury at 0 C. for

. proper temperature compensation, while the fllling of gas in a capsule employed as in Fig.5 may preferably be at a pressure of. one inch of mercury. In this way thecapsule Din Fig. 6 compensates for temperature variations for the en-- tire gang-of three capsules.

What 1 claim and desire ,to sec re by united j :States' Letters Patent is: 1; An aheroid capsule comprising a circular diaphragm having a central movable operator and concentric corrugations deeperatthe margin than near the center thereby of shapes and relative sizes designed to. accord best for faithful response .to variations in external pressure when i said capsule is' completely evacuated .and functions at constant temperature; and internal chamber completing and volume limiting structure having an external flxable central. mount and provisions tending to hold all said volume limiting structure by-said mount against movement due to inertia forces, said structure having a peripheral hermetical seal to the rim of said circular diaphragm and being. provided with concentric corrugations complementary to the 'inner face corrugations of said circular diaphragm -whereby the volume of the chamber of said cap- I sule may be predetermined approximatelydown to zero plus the volumeyariation due to opera,- tive movements ofsaid circular diaphragm. V a v 2. An aneroid capsule comprising two opposed tions deeper at the margin than near the center and thereby of shapes and'relative sizes. designed toaccor'dbest for faithful response to variations in external pressure when. said capsule is completely evacuated and isjunctioning at constant temperature, said capsule being symmetrical rel- 'atively .to a central axis and relatively,to a'centr'al cross-section and forming an internal.

chamber; an external central operator for one diaphragm; a flxable central mount for'the other diaphragm; an internal solidflller having op- I positely positioned concentric corrugations complementary to the inside faces of the corrugations of said circular diaphragms; wherebyxthe:

gasspace in said chamber may be predetermined in volume regardless of the chamber space de' fined'bysaid concentric corrugations of said circular diaphragms; and provisions tending to hold said filler by said fixable mount against movement due to inertia forces? evacuated and one or more of which are char acterized as set forth in claim 1 whereby tem- 3. A gang of several tandem connected aneroid capsules, a plurality of which are completely perature compensation and a wide range of operative aneroid movement result. 1

4. An aneroid device comprising a corrugated flexible member defining a wall of an aneroid chamber,'a filling of permanent gas within said aneroid chamber at less than atmospheric pres- ,sure, and means for determining the amount of said gas at the predetermined pressure within said aneroid chamber- 5. An aneroiddevlce comprising acorrugated -flexible member defining a wall of an.'aneroid.

chamber, a filling of permanent gas within said aneroid chamber at less than atmospheric pressure, and means for determining the amount of said gas at the predetermined pressure within 7 said aneroid chamber comprising a solid filler corrugated discs, means member occupying a substantial portion of the volume of said aneroid chamber.

6. An aneroid device comprising acorrugated elastic metal member forming a wall of an aneroid chamber, a member having complementary corrugations cooperating therewith to reduce the volume of the aneroid chamber, and a filling of permanent gas in said chamber of such quantity that with atmospheric pressure upon the capsule, the gas pressure within said capsule nal pressure and a charge of fixed gas in one of said chambers of predeterminable proportion to the flexible wall construction responsive to said variations in said external pressure. which proportion is independent of the proportion that the natural internal chamber space bears to the reis a relatively small fraction of atmospheric pressure, the volume of the. aneroid chamber being such that at changed temperatures and pressures the elastic efiect of said gas compensates for the change in elasticity of the said capsule. 7. An aneroid capsule comprising a v for sealing the margins of said discs together to form an air-tight chamber, the corrugations of said discs being substantially similar and opposed, and a filler member within said capsule chamber having surface contours upon opposite sides, matching the corrugations of said capsule discs.

- 8. An aneroid capsule comprising a pair of pair of 'silient wall area and operating in combination with the resilience of a resilient wall portion to effect a predetermined temperature. compensation.

12. A pressure responsive device comprising in combination an expansible gas-tight chamber formed at least partly by a resilient diaphragm acted upon on one side by an external pressure, changes of which pressure within the operating range of the device cause an appropriate move-' ment of the diaphragm inward or outward from one position into another; and a charge of gas, inside said chamber acting on the other side of the diaphragm, the charge of gas being at a predetermined pressure which is at all times considerably lower than the external pressure, the gas being subject to expansion in substantially inverse proportion to the load acting on the diaphragm up to a multiple of its volume consumed in one extreme position of the diaphragm upon movement into the other extreme position, whereby said diaphragm will be moved in true response to changes in external pressure irrespectiveoi changes in temperature affecting its resiliency,

the action of the gas on the diaphragm upon a certain temperature change being relatively strong at high external pressure in which the charge of gas assumes a small volume and-the action of the gas being relatively weak at low 35 external pressures at which the charge of gas is considerably expanded.

13. A pressure responsive device comprising in combination an expansible gas-tight chamber 4 formed at least partly by a resilient diaphragm corrugated discs, means for sealing the margins of said discs together to form an air-tight chamber, the corrugations of said discs being substantially similar and opposed, a filler member within id'capsule chamber haying surface contours,

upon opposite sides, matching the corrugations of said capsule discs, and a filling of temperature sensitive permanent gas within said capsule of such quantity as to compensate for temperature changes of ambient air.

, 9. An aneroid capsule comprising a solid member having surface corrugations, an elastic disc member attached thereto having corresponding corrugations of said plate member, defining an aneroid chamber, and a filling of temperature termined pressure which is at all times considsensitive permanent gas therein adapted to maintain a pressure within said aneroid chamber variable according to the temperature of ambient air. .10. An aneroid capsule comprising a pair of elastic corrugated members having matching corrugations, one being adapted toenter -into an annular portion of another, both members being elastic and adapted to respond to variations of pressure thereon, and a filling of temperature sensitive permanent gas within the aneroid chamber between said corrugated members, the volume of the said aneroid chamber being such that the variations oi pressure 6f said permanent gas with variation of the temperatureof ambient air compensates for temperature deviations of the instrument..

11; An external pressure responsive aneroid type device comprising one or more hermetically closed partially evacuated chambers each having an indicator actuatingresili'ent wall construction acted upon on one side by an external pressure, changes of which pressure within the operating range of diaphragm irom one position into another; afiller body inside said chamber filling the greater part of said chamber when the diaphragm is moved the 'device cause a movement oi'the into the one extreme position, whereby the residual volume of the chamber will be greatly enlarged by a movement'oi the diaphragm into the other extreme position; and a charge of gas insidesaid chamber and acting on the other side of said diaphragm, the charge of gas being at a predeerably lower than the external pressure and being subject to substantial changes in volume upon movementsof said diaphragm, whereby said diaphragm will be moved in true response to changes in'external pressure irrespective of changes in temperature afiecting its resiliency, the actioncf the gas on the diaphragm upon a certain temperature change being relatively strong at high external pressures in which the charge of gas assumes a small volume and the action of the gas being relatively weak at low external pressures at which the charge of gas is considerably expanded.

14. A pressure responsive device comprising, in combination, a corrugated metallic diaphragm; a

- wall member having corrugations complementary resilientlyresponsive to variations in said exterto the corrugations of said diaphragm and permitting a snug fitting of the diaphragm upon deflection towards said wall member without actual contact, said wall member being tightly connectedlto said diaphragm at the rim portion of the latter thus completing a gas-tight chamber enclosing a very smallvolume in a'compressed stateand a proportionately greatly enlarged volume in an expanded state; a charge of gas inside said chamber, said charge of gas being at a pre- 5 determined pressure which is at all times considerably lower thanthe external pressures for which the device is designed, said gas being expansible from its volume assumed in one extreme position of the diaphragm corresponding to a greatestlexe ternal. pressure to a relatively greatly enlarged volume. upon movement of thediaphragm, into? the other extreme position corresponding tothe" lowest external pressure for which the ,device' is designed; whereby said diaphragm will-be moved l5 irrespective of changes-in temperature aflecting its resilierlcy, the compensating action of the gas onthediaphragm .upon -a certain temperature change being relatively strong at high external go pressures in which the charge or gas assumes a small volume and the-action of the gas being rela tively weak at low exte'rnal-pressuresat which the charge of gas, is considerably expanded. V

' -15. A pressure responsive device comprising, in

25 combinations corrugatd metallic diaphragm; a

rigid wall member having corrugations complein 'trueresponse to changes in external pressure on the diaphragm upon a certain temperatm'e I change being relatively strong .at high external pressures in which the'charge' 01' gas assumes-a small volume and the action 'oi'the' gas being relatively weak at low external pressures at which .the charge oi! gas is considerably expanded.

16.- A pressure responsive device comprising in combination, a1 first corrugated metallic diaphragm; a second metallic diaphragm having corrugations vcomplementary to the corrugations of said first diaphragm and permitting a'snug fitting of saididiaphragms close to each othenupondeflection. oi the same without actual co'ntactfsaid diaphragms being tightly connected at the rimportions, thus completing a gas-tightdiap hragm. chamber; and a charge oigas inside said chainher, said chargeof gasbeing at a predetermined' pressurewhich is-at all times lower'than external- I pressures for which the deviceis designed, said Y mentary to the corrugationsfoi" said diaphragm' and; permitting a snug fitting of the diaphragmupo'n deflection towards said wall member With-,- 0 out actual contact, saidwall member being'tightlym connected to said diaphragm at the rim portion 1 oithe latter thus completing a gas-tight, chamber enclosing a very small volume 'in a'compressed state and a relatively greatly enlargedvolumein said chamber, said charge of gas being at a prean expanded state; and a-charee of gas inside determined pressure which is at alltimes cOnsid;-.'

erably lower than external pressures'forwhich. the device is designed, saidwgas being expansiblc 40 from its volume assumed in one extreme position -offlthe diaphragm 'corresponding'to a greatest external pressure to 'a relatively greatlyenlarged volume upon movement of the diaphragm into.

the other extreme position corresponding tothe designed, whereby said diaphragm will be moved its resiliency,

lowest:exter'nal pressure for which the device is pressures in which the, charge oi'gas assumes a V relatively weak at low external pr gas being expansibie upon ex'pansio'nvof said diaphragm or diaphragms to a chamber enclosmg a.

-multiplefof the-volume assum'edbythe gas in the compressed *state of the V v whereby said diaphragm chamber will be moved a in true response to changes in atmospheric pres I jsure'acting on the outside of th same irrespective:

of changes in temperature aflecting its resiliency,

- the compensating action ofut'he gas on the diaphragms in response to a certain temperature change being relatively strong at high external small. volume and the action otth'e gas being r s at which the charge or gas is con'siderablyexpanded, 1'7. In an atmospheric pressure responsive devicethe combination with an evacuated first diaphragm capsule Tconnected in tandem with said "resilient capsule; .of asecond resilient first capsule;"a flller' member inside said second I "capsu-le fillinglthe greater-part0! the capsule in the condition in which thecapsule is compressed and permitting the fi idual'i olume to become:

greatly enlarged-upon an expansion of the capsule; and a charge of gas inside'said second capsule, the charge-oi gas b at a predetermined pressure whichis at all lower than the externaitatmospheric pressure;

times considerably 

